Vibration damper for rotating shaft

ABSTRACT

A vibration damper has a pair of rollers that engage a shaft rotating about its longitudinal axis while being supported at its ends on centers. The rollers transmit shaft vibrations to the piston rod of a hydraulic or pneumatic cylinder in such a manner that the piston rod dampens the vibrations.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority of Provisional PatentApplication filed May 30, 2003, Serial No. 60/474,137 for VIBRATIONDAMPENER FOR ROTATING SHAFT.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] Steel shafts, such as an axle, are commonly finished by beingmounted on a pair of rotating centers. The rotating shaft sometimesgenerates harmonic vibrations. Such vibrations are undesirable forachieving a precision finish on the shaft surface.

[0003] The broad purpose of the present invention is to provide adamping device for reducing the vibrations of a rotating shaft. In thepreferred embodiment of the invention, a pneumatic or a hydraulic powercylinder is mounted on a base, adjacent the rotating position of theshaft. The axis of the cylinder is aligned with and at a right angle tothe centerline of the shaft. The piston rod is connected to a cleviswhich in turn is connected to a slide plate. The slide plate moves withthe piston rod and either toward or away from the shaft. A pair ofpivotal arms, mounted on the base, are cammed by the slide plate.

[0004] Rollers mounted on the outer ends of the arms engage theworkpiece, accommodating any misalignment of the workpiece. The slideplate carries a pair of cam rollers that are mounted in cam slots in thetwo arms. The arrangement is such that any vibration of the workpiece istransmitted through the arms, the plate slide and to the cylinder whichdampens the vibrations.

[0005] Still further objects and advantages of the invention will becomereadily apparent to those skilled in the art to which the inventionpertains upon reference to the following detailed description.

DESCRIPTION OF THE DRAWINGS

[0006] The description refers to the accompanying drawings in which likereference characters refer to like parts throughout the several viewsand in which:

[0007]FIG. 1 is an elevational view of a vibration damper illustratingthe preferred embodiment of the invention;

[0008]FIG. 2 is a view similar to FIG. 1, but showing some internalcomponents in phantom;

[0009]FIG. 3 is an enlarged view of one of the arms as seen from theleft-side of FIG. 2;

[0010]FIG. 4 is an enlarged view as seen along line 4 of FIG. 2;

[0011]FIG. 5 is an enlarged view as seen along line 5 of FIG. 2;

[0012]FIG. 6 is an enlarged view as seen along line 6 of FIG. 2;

[0013]FIG. 7 is a plan view of the base separated from the remainder ofthis device; and

[0014]FIG. 8 is an elevational view of the slide plate.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0015] Referring to the drawings, FIGS. 1 and 2 illustrate a preferredvibration damper 10. The vibration damper includes a cushioningpneumatic power cylinder 12, such as a global series cylinder, doubleacting, single rod model, mounted in a vertical position on a suitablemounting bracket 14, illustrated in phantom. The power cylinder has apair of ports 16 and 18 connected to a source of pneumatic pressure, notshown, for reciprocating an internal piston, not shown. A clevis 20 isattached to a piston rod 21 to reciprocate toward or away from thecenterline of an elongated workpiece 22. The workpiece may be a shaft oran axle undergoing a metal finishing operation. The levis is movablealong an axis 24 either toward or away from the center of workpiece 22.

[0016] Referring to FIGS. 4 and 7, a right angle base 26 has one wall 28attached by fastener means 30 to the upper end face of the cylinder.Wall 28 has an opening 32 to accommodate the up and down movement of theclevis.

[0017] Referring to FIGS. 4-6 and 8, a slide plate 34 has a lower endconnected to the clevis by a pin 36 such that as the clevis is moved bythe power cylinder toward the workpiece, the slide plate moves an equaldistance.

[0018] The slide plate has a vertical slot 38 aligned with axis 24 ofpiston rod 21.

[0019] Referring to FIG. 4, a shoulder screw 40 and a jam nut 42 aresupported in a horizontal position to base 26. Screw 40 extends throughslot 38 in the slide plate to the base.

[0020] Referring to FIGS. 2, 5 and 8, the slide plate has a pair ofopenings 44 and 46 located on opposite sides of slot 38. A pair of dowel(pivot) pins 48 and 50 are mounted in the two openings 46 and 44,respectively. Pins 48 and 50 are both mounted on the base.

[0021] Elongated pivot arms 52 and 54 are pivotally mounted on pivotpins 48 and 50, respectively. Arm 52 is pivotally movable from a lowerrelease position, illustrated at A in FIG. 1, to an upper work-engagingposition, illustrated in phantom at B. Similarly, arm 54 is pivotallymovable from a lower release position C to an upper work-engagingposition D. Arm 52 has a cam slot 56. Arm 54 has a cam slot 58. Camslots 54 and 56 are each aligned with the center of their respectivepivot pins.

[0022] Referring to FIGS. 2 and 6, the slide plate carries a cam roller60 which is disposed in cam slot 58. As the slide plate rises towardworkpiece 22 in a vertical motion, as viewed in FIG. 2, cam roller 60rises along a linear path of motion from a lower position, illustratedin phantom in FIG. 2, toward an upper position also illustrated inphantom. Cam roller 60 moves in cam slot 58, camming arm 54 from itslower position toward its upper position.

[0023] Referring to FIGS. 1 and 2, a pair of floppy brackets 62, onlyone shown, are pivotally mounted by a pin 63 on the outer end of pivotarm 54. Workpiece-engaging rollers 64 and 66 are mounted in a spacedposition on the outer end of brackets 62 by roller pins 68 and 70,respectively. Dowel pin 72, carried by the brackets, engages a channel74 carried on arm 54 to limit the swing of rollers 64 and 66 about pin63.

[0024] Referring to FIGS. 2 and 6, the slide plate has a second rolleror cam follower 75 carried in cam slot 56, camming arm 52 from a lowerposition, illustrated in solid in FIG. 2, to a raised position, alsoillustrated in phantom toward the workpiece.

[0025] Referring to FIGS. 2 and 3, a second pair of floppy brackets 76and 77, similar to brackets 62, are mounted by a pivot pin 78 on theouter end of arm 52. The brackets carry a pair of rollers 80 and 82 onpins 84 and 86, respectively, for engaging the workpiece. A dowel pin 88carried by brackets 76 and 77 engages a channel-shaped cut-out in arm 52to limit the pivotal motion of rollers 80 and 82 as they swing about theouter end of the arm 52.

[0026] Thus it is to be understood that I have described avibration-dampening device for reducing the vibration of an elongatedrotating workpiece 22. Usually the workpiece will be delivered to amounting position between arms 52 and 54, and placed on rotatingcenters. Arms 52 and 54 are pivoted toward the workpiece until rollers80, 82, 64 and 66 engage the workpiece at 900 intervals, as illustratedin FIG. 2.

[0027] The floppy brackets which carry rollers 80, 82, 64 and 66 permitthe two arms to be self-aligning to accommodate irregularities in theworkpiece shape.

[0028] In use, the damper is mounted, at a suitable location along aworkpiece. The piston rod moves the slide plate in a vertical motion,rising to move the rollers either toward the workpiece, or lowering tomove the arms toward this lower position to separate the cam rollersfrom the workpiece. Any vibration of the workpiece is transmittedthrough the arms and slide to the piston rod where the vibration iscushioned.

Having described my invention, I claim:
 1. A vibration damper for anelongated workpiece rotating about an axis, and vibrating in a directionlateral to said rotating axis, comprising: at least oneworkpiece-engaging roller supported for rotation about an axis parallelto a workpiece-rotating axis; mechanical means connected to said rollerfor moving the roller into engagement with the rotating workpiece torotate therewith, and for moving with the workpiece in a directionlateral to said rotating axis as the workpiece is vibrating; a fluidcylinder having a reciprocally, resiliently mounted piston rod, movablewith respect to said cylinder; said mechanical means being connected tosaid piston rod and said roller to resist a radial motion of the rollercarried by the workpiece.
 2. A vibration damper as defined in claim 1,in which the piston rod reciprocates along an axis that intersects therotating axis of the workpiece.
 3. A vibration damper as defined inclaim 1, including a plurality of rollers each supported for engagingthe workpiece, said mechanical means being operative to move saidplurality of rollers toward the workpiece, and being connected to thepiston rod to resist a vibrational movement of the workpiece.
 4. Avibration damper as defined in claim 3, in which the plurality ofrollers engage the workpiece in equal angularly spaced locations aboutthe workpiece.
 5. A vibration damper for an elongated workpiece rotatingabout an axis and moving in a vibrational movement in a directionlateral to said rotating axis, comprising: a base; a cylinder mounted onthe base and having a piston rod movable in a direction transverse tothe rotating axis of a workpiece; a slide plate connected to the pistonrod so as to be movable therewith; a first arm, and first pivot meansconnecting the first arm to the base for a pivotal motion, the first armhaving a camming slot; a first cam roller carried by the slide plate andreceived in the camming slot of the first arm, such that as the slideplate moves toward the workpiece, the first arm swings along a firstpath of motion about said pivot means toward the workpiece; a firstfloppy bracket, and pivot means connecting the first floppy bracket tothe first arm to swing the arm toward the workpiece as the first armswings in said first path of motion; a pair of spaced rollers carried onthe first floppy bracket to engage the workpiece on a first sidethereof; a second arm and second pivot means connecting the second armto the base for a pivotal motion, the second arm having a camming slot;a second cam roller carried by the slide plate and received in thecamming slot of the second arm such that as the slide plate moves towardthe workpiece, the second arm swings along a second path of motion aboutsaid second pivot means toward the workpiece; a second floppy bracketand pivot means connecting the second floppy bracket to the second armto move toward the workpiece as the second arm swings in said secondpath of motion; and a pair of spaced rollers carried on the secondfloppy bracket to engage the workpiece on a second side thereof wherebya vibrational movement of the workpiece is transmitted from the rollerson the floppy brackets to the first arm and the second arm, and then tothe slide plate and the piston rod such that the piston rod resists saidvibrational motion.